Electric rare gas filled lamp



June 15, 193?. A. YLEDERER 2,084,03?

ELECTRIC RARE GAS FILLED LAMP Filed Dec. 20, 1930 INVENTOR AntonLeder'er,

afia ATTORNEY -cury in the lamp Patented June 15, 1937 UNITED STATESPATENT OFFICE Anton Lederer, Vienna,

zer and General Co said Anton Lederer,

Ernest Anton Lederer,

nrad Randa,

Catherine Daub executors of deceased, more to Glen Ridge, N. J.

Austria;

Application December 20, 1930, Serial No. 503,804 In Austria December28, 1929 Claims. (Cl. 176-122) This invention relates to electric raregas filled lamps, and more especially to those of the class disclosed inmy prior co-pending applications, Ser. No. 468,884 filed July 18, 1930,and Ser. No. 497,025 filed November 20, 1930, containing electrodeswhich are so spaced apart in relation to the rare gas pressure that therare gas is excitable thereby to luminescence as an intense aureole.

In lamps of this kind which have hot electrodes or at least a hotcathode and wherein the rare gas filling sometimes with an admixture ofother gases, has an addition of mercury, a rise in temperature in theinterior of the lamp, above that which is necessary for its properoperation is often disadvantageous owing to overheating or excessiveevaporation of the mercury by which the lighting effect of the lamp isunfavourably infiuenced the lamp giving a bluish light. This phenomenondepends also on the position of the liquid mercury with respect to thegas filling of the discharge space. For instance, in the case of neonand other rare gas filled lamps containing an addition of mercury andoxide electrodes, hot electrodes heated by heating wires of a diameterof about 0.12 to 0.13 mm. for example, more or less evaporation of themercury will take place, according to the pos'tion of the lightingportion of the lamp. This is because the part containing the liquidmercury may be more or less easily accessible to the heated neon gas;consequently the light which with proper evaporation of the merom iswhite or nearly white is strengthened at the violet end of the spectrumby the formation of an excess of mercury vapour or by the overheating ofthe mercury so that the lamp emits a bluish light.

According to the present invention this disadvantage is removed bylocating the liquid merin such a manner that it is not exposed directlyor in its entirety to the heat of the heated gas filling in thedischarge space of the lamp. Excessive heating and evaporation of themercury and consequently with some lamps a bluish light due to themercury is thereby avoided.

One method of carrying out the invention is to locate the liquidmercury, and in some cases also the getter which is a material employedfor the purpose of freeing the filling gas or gases from the last tracesof impurities, in a part of the lamp beneath the discharge space. Theliquid mercury is therefore not so directly, or at least not in itsentirety, exposed to the action of the heated gases and excessiveevaporation is avoided. Also, the quantity of liquid mercury to beintroduced need not be measured exactly because the whole of the mercurywill not evaporate. When however the liquid mercury is located above thedischarge space, the exact and correct quantity of mercury is dimcult tofind, for instance, in the case of a lamp taking a current of from 0.4to 0.5 ampere, because under the intense action of the circulatingheated gases a very intense evaporation of the mercury takes placemostly extending to the whole amount of mercury present.

It is advantageous to have the liquid mercury located beneath thedischarge space in the neck of the lamp. This neck may be at any desiredposition in the lighting part of the lamp container, provided it isbeneath the discharge space. In the case of an electric gas-filled lampwith a globe shaped glass bulb and a neck, the mercury, and in somecases placed in the neck and vertical or inclined position so that theneck extends downward perpendicularly or at an angle and consequentlylies beneath the discharge space.

In another method tion the part of the the lamp is used in a of carryingout the invenlamp containing the liquid mercury, and in some cases thegetter also, is

separated from the discharge space of the lamp by a partition which doesnot prevent communication between these parts, that is to say the accessof gas from one part to the other, but renders it more diflicult. Thepartition may be, for example, a plate leaving an annular passage free.By the partition an excessive evaporation of the mercury is preventedand the circulation of the gas into the space which contains the liquidmercury is limited. The partition is preferably made of an insulating,heat insulating or electrically insulating material, such for instanceas mica, glass, quartz or the like; it is further advisable to use atransparent material for the partition. 4

Both the methods above described may be combined by locating the mercuryand the getter in a neck lying beneath the discharge space, the interiorof which neck is' almost completely separated from the discharge spaceby means of a partition so arranged that between the interior of theneck and the discharge space the passage of gas can still take place.

The accompanying drawing is a view, somewhat diagrammatic, illustratingby way of example only an electric lamp constructed in accordance withthe invention.

Referring to the drawing, l is a globe or portion the getter also, maybe depending carrier of the lamp intended to emit light; 2 are theelectrodes provided with leading in wires 3 and supported on supports 4in an ordinary manner. The

globe I has a downwardly extending neck 5 in and is of such diameterthat its edge is spaced apart from the neck as indicated at ii.

In the manufacture of the lamp the getter is located on the ring]; andwhen vaporized deposits on the neck portion 5 of the-lamp bulb so thatit does not interfere with the emission of light through the globe I.

The liquid mercury is contained in the bottom of the neck as shown at Hand is screened from the direct heat of the discharge space'in the globeI by the partition 8. Free communication between the. space in the neckand the discharge space is allowed round the edge of the partition.

When a getter is used and vaporized from the ring 6 it will deposit onlyon the neck portion.

No claim is made in this application for the construction of the lightemitting portion of the lamp per se as shown in the upper part of thedrawing, such being claimed in my co-pending application hereinbeforereferred to.

I claim:

1. An electric illuminating lamp comprising an envelope having a fillingconsisting of at least one rare gas, cooperating electrodes therein atleast one of which is of the indirectly-heated by avoid predominance ofmercury light.

2. An electric illuminating lamp comprising an emissive type, means forapplying a potential between said electrodes, said electrodes havingsuch a spacing in relation to the rare gas pressure that the rare gas isexcitable thereby to luminescence as an intense aureole, and a smallquantity of mercury located within a part of said envelope in a positionwhere the mercury will be subject to the heat of the hot rare gas and bevaporized thereby, said mercury containing part of the envelope beingremoved from the gaseous discharge space and having such restrictedcomenvelope having a main munication therewith in relation to theheating effect of the hot rare gas on the mercury in said position thatthe mercury will be vaporized incompletely and to anextent to produce asubstantially white light.

3. An electric illuminating lamp comprising an envelope having a fillingconsisting of at least one rare gas, cooperating electrodes therein atleast one of which is of the indirectly-heated electron emissive type,means for applying a potential between said electrodes, said electrodeshaving such a spacing in relation to the rare gas pressure that the raregas is excitable thereby to luminescence as an intense aureole, a smallquantity of mercury located in a partof said envelope which is out ofthe gaseous discharge path, the mercury in said art of the envelopebeing in a position to be heated and thereby vaporized by the hot raregas, and a partition largely but not completely screening said mercuryfrom the gaseous discharge path and shielding the mercury in said partof the envelope from the heat of the hot rare gas and therebycontrolling the vaporization of the mercury so as to avoid predominanceof mercury light.

4. An electric illuminating lamp comprising an envelope having a mainportion and a neck portion through which electrical leads pass andhaving a filling consisting of at least one rare gas, cooperatingelectrodes in the main portion of the envelope at least one of which isof the indirectlyheated electron emissive type, means for applying apotential between said electrodes, said electrodes having such a spacingin relation to the.

sage that the mercury will be vaporized to an ex- 4 tent which willavoid predominance of mercury light.

5. An electric illuminating lamp comprising an portion and a neckportion through which electrical leads enter, a filling of at least onerare gas and mercury vapor, cooperating electrodes in the main portionof the envelope at least one of which is of the indirectlyheatedelectron emissive type, said cooperating electrodes being capable ofexciting both the rare gas and the mercury vapor to luminescencesimultaneously, a getter substance deposited on said neck portion of theenvelope, and a partition mainly but incompletely separating said neckportion from the main portion of the envelope.

ANTON LEDERER.

